title: Estimating the refractive index of pharmaceutical solids using predictive methods.
abstract: Refractive index is a basic physical property of pharmaceutical solids. In this paper, the refractive index values of 424 pharmaceutical solids from the literature were surveyed. It was found that the refractive index values exhibit a normal distribution with an overall mean value of 1.603. The Eisenlohr and Vogel methods developed for organic liquids were employed to estimate the refractive index for pharmaceutical solids. The estimated results were compared with experimentally measured values determined by polarized light microscopy. Both Eisenlohr and Vogel R(D) methods agreed very well with the measured mean refractive index values from the literature with an average absolute percent error of 1.22% and 1.25%, respectively. The evaluation for in-house measurements for Pfizer active pharmaceutical ingredients showed larger differences between the calculated and measured values. The results indicate that the Eisenlohr and Vogel R(D) methods can provide fast and accurate results for predicting the refractive index of pharmaceutical solids.
authors.affiliation: Pfizer Global Research & Development, Eastern Point Road, Groton, CT 06340, USA. xiaoping.cao@pfizer.com
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Cao
authors.forename: Bruno C
authors.initials: BC
authors.lastname: Hancock
authors.forename: Norma
authors.initials: N
authors.lastname: Leyva
authors.forename: Jennifer
authors.initials: J
authors.lastname: Becker
authors.forename: Weili
authors.initials: W
authors.lastname: Yu
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Masterson
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods*; D002627:Chemistry, Physical; D003627:Data Interpretation, Statistical; D005544:Forecasting; D008859:Microscopy, Polarization; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D012031:Refractometry
chemical_list: D004364:Pharmaceutical Preparations